To get the reward Suirin Obi in the quest "In the In the Name of Science." you trade Yurim (First Floor, Tavnazia) a Silver Obi, blue color chip, and Hpemde Organ and a Phuabo Organ.
this only works for spells so far frrom what i have seen. Here is a link showing the wind obi does not work for equipment. http://ffxi.allakhazam.com/db/jobs.html?fjob=10&mid=1116055437155823749&num=16
I am not sure if his find is accurate...if you look at the pictures he shows he has both the Obi snd the dagger equiped at the same time, so he could have Wind-15 and then when he equipted both it was Wind+15...but that is just what i think...I could be way off ^^;; Just thaught i would let you know what it thaught
All elemental magic would get bonuses from this to, if I were to cast water magic on watersday with water weather [rain >.>] I bet I'd hit harder than without this.
So would the wind version of this also allow "Mighty" weapons and the like to do their "On windsday:" damage as well? that would be very useful cos Mighty Knife is one of the best daggers in the game with its windsday effect
They're supposed to give you the benefits of each day/corresponding weather pattern depending on which belt you wear i.e Suirin Obi=benefits of Watersday/water weather, which makes them extraordinarily useful for SMN's with Relic body or head pieces, as well as in conjunction with other pieces of equip which have a stat dependent on either day or weather effects.
For more info check here http://ffxi.cannotlinkto/questdb/422